Question

QUESTION 1

Which of the following occur(s) during Pol II transcription preinitiation complex formation? (More than one correct answer possible. Mark all that apply).

A) TFIIB unwinds the DNA.

B) TFIIB contacts both TATA box-binding factor and the DNA.

C) DNA bends.

D) TFIIA binds to TFIIB.

Question 2

An enhancer (select all that apply)

A) is a DNA element that interacts directly with general transcription factors to enhance or repress transcription.

B) is a protein that binds to a promoter and enhances its activity.

C) is a protein that binds to RNA polymerase and enhances transcription.

D) interacts with repressor proteins to enhance transcriptional repression.

E) is a DNA control element that can be located at a great distance upstream or downstream of a promoter.

F) acts as a binding site for RNA polymerase.

QUESTION 3

An important early step before transcription initiation that leads to gene expression is

A) Rapid packaging of DNA into condensed chromatin assuring the activity of all the genes in eukaryotic cells except those whose transcription is repressed by specific negative regulatory mechanisms.

B) relief of transcription repression by chromatin remodeling and the removal of neucleosomes to transiently expose promoter DNA.

C) the coiling of DNA around a set of eight histones in the nucleosome.

D) DNA binding by TATA binding protein (TBP).

QUESTION 4

The activation domains of transcriptional activators

A) can be swapped with another activation domain to create a new chimeric transcription factor.

B) can interact directly with the promoter.

C) can facilitate transcription by catalyzing RNA polymerization

D)can bind to DNA.

QUESTION 5

The mediator complex

A) can form a molecular bridge between activators of transcription and DNA replication machinery.

B) can function to maintain nucleosomes at promoter regions in a hypoacetylated state (facilitating nucleosome stability and chromatin condensation).

C) transduces regulatory signals between activation (and repression) domains of transcription factors bound to distal DNA elements (e.g. enhancers) and RNA polymerase II by binding directly to both.

D) is a small, a 30-residue long protein that forms a molecular bridge between activation domains of transcription factors and their DNA binding domains.

QUESTION 6

Transcription factors can do all of the following EXCEPT

A) Synthesize RNA.

B) undergo conformational changes which alter activity.

C) act to repress transcription of transcription factor genes.

D) exist as heterodimers.

E) respond to extracellular signals.

QUESTION 7

Which of the following statements concerning the Mediator is correct?

A) Some of the mediator subunits bind to the DNA at distal sites and at enhancers while other subunits simultaneously bind the DNA at promoter proximal sequences.

B) Most of the yeast Mediator subunits are unique and have no homologs

in cells of higher eukaryotes (e.g. flies and humans).

C) The mediator acts as a bridge between transcription factors binding at distal sites and enhancers on the one hand and the basal transcription initiation machinery including RNA pol II at promoter sites.

D) The major mediator subunits can trace their evolutionary origin to bacterial σ factors.

E) All of the statements, including this one, are true.